OCR A 3.1.3 · 20 written questions · 41 marks · about 50 minutes · marked as you go
This free quiz has 20 written exam questions on transport in plants, all taken from OCR A Level Biology A papers (AS and A level, 2017 to 2025). Short answers and calculations mark themselves. For longer answers you write your answer, then tick off the OCR mark-scheme points you made, so you see exactly where the marks are. The quiz covers all of OCR A 3.1.3, from why multicellular plants need a transport system to how sucrose is loaded into the phloem. It mixes micrograph identification, potometer calculations, a fill-the-gaps question on water pathways and a 'spot the errors' question on active loading.
What the quiz covers (OCR A spec 3.1.3)
The need for transport (3.1.3(a)): size, SA:V and diffusion, with an SA:V calculation and examples of what plants transport.
Xylem and phloem (3.1.3(b)): naming cells and tissues in photomicrographs and drawings of roots and stems, xylem structure and adaptations, and how to show xylem in a celery stalk.
Transpiration (3.1.3(c)): what causes it, the factors that affect it, why light intensity matters, and using a potometer to calculate a rate.
Water movement (3.1.3(d)): the apoplast and symplast pathways, the Casparian strip and the transpiration stream.
Adaptations to water availability (3.1.3(e)): xerophyte leaf features and how xylem differs in hydrophytes and cacti.
Translocation (3.1.3(f)): active loading of sucrose by companion cells, the role of protons and cotransporters, and why sucrose is the sugar transported.
How to use it
Write every answer in full, as you would in the exam: the mark for each question is shown, so you know how much to write. When you self-mark, only tick a point if your answer clearly makes it, then read the examiner's tip under each question. Your progress is saved on your device, so you can do it in two sittings, and at the end you can retry just the questions where you dropped marks.
Prefer multiple choice? Try the 29-question Transport in Plants multiple choice quiz first.
Open the Transport in Plants quiz in a new tab (easier on a phone)
Where students lose marks (from OCR examiners' reports and mark schemes)
Each point below is followed by wording that gained marks.
Whole plants have a low SA:V: Some students say multicellular plants have a large SA:V, confusing a whole plant with an organ like a leaf that has a large surface area.
✔ Gains credit: A large multicellular plant has a small SA:V and long diffusion distances, so diffusion alone is too slow; water and ions must be carried from roots to leaves.
Protons are pumped, sucrose is cotransported: 'Active transport of sucrose' is not credited, and many think ATP drives the cotransporter or that the proton pump is a cotransporter.
✔ Gains credit: Carrier proteins actively pump H⁺ out of the companion cell; H⁺ flow back in by facilitated diffusion through cotransporter proteins, bringing sucrose with them (active loading).
Name the cell if asked for cells: Students give the tissue (phloem, xylem) when the question asks for the cell, or give a cell (xylem vessel, sieve tube) when it asks for the tissue.
✔ Gains credit: Cells: sieve tube element, companion cell, xylem vessel. Tissues: phloem, xylem, cambium.
Thick waxy cuticle, not thick epidermis: Students write 'waxy cuticle' without 'thick' (all plants have one) or say 'thick epidermis' instead.
✔ Gains credit: Xerophytes have a thick(er) waxy cuticle, which reduces transpiration / stops water vapour escaping.
Vessel wall, not cell wall: In xylem diagrams, students write 'cell wall' for the lignified wall, 'hollow tube' for the lumen and 'plasmodesmata' for pits.
✔ Gains credit: Lignified vessel wall, lumen, and (bordered) pits that let water move sideways between vessels.
Potometers measure uptake: When asked for the assumption behind a potometer, students describe how to set it up instead.
✔ Gains credit: The potometer measures water uptake, so we assume all the water taken up is lost by transpiration and none is used by the plant.
Halve the diameter, scale the time: In potometer calculations, students use the diameter as the radius, forget to square it, or don't convert the time period to the unit asked for.
✔ Gains credit: Volume of water = πr² × distance moved, with r = diameter ÷ 2, then scale to the time unit in the question (e.g. × 2 for 30 minutes to per hour).
Change one variable at a time: When adapting a potometer to test air movement, students add a fan but leave the humidity dome on, so two variables change at once.
✔ Gains credit: Remove the plastic dome and spray, then place a fan at different distances or on different speeds.
Keep practising
Try the Transport in Plants multiple choice quiz, the Photosynthesis quiz, the Transport in Animals written quiz, or browse all our OCR A Level Biology quizzes. Our OCR A masterclasses (Year 12 on Wednesdays at 5.15pm, Year 13 on Tuesdays at 6.30pm) work through real exam questions on one topic each week.
Questions, mark schemes and examiners' report extracts © OCR.